1. Field of the Invention
The present invention relates to a parameter setting method.
2. Description of the Related Art
Conventionally, in the case where an image was captured by a camera out of focus, it was necessary to recapture the image after performing focusing again. Further, in the case where it was desired to obtain focused images of a plurality of subjects the depths of which are different, it was necessary to capture the image of each subject in focus a plurality of times.
In recent years, a technique called light field photography has been developed, which is capable of adjusting the focus position in the later image processing (refocus) by adding a new optical element to the optical system to acquire images from multiple viewpoints (a plurality of viewpoints).
With this technique, there is an advantage that a failure in focusing at the time of image capturing can be made up by image processing because it is possible to perform focusing after image capturing. Further, there is also an advantage that it is possible to obtain a plurality of images focused on arbitrary subjects in an image from one captured image by changing the image processing method, and therefore, it is possible to reduce the number of times of image capturing.
In light field photography, the direction and intensity of a light beam that passes through each position (light field, hereinafter, referred to as “LF”) in a plurality of positions in the space are calculated from multi-viewpoint captured image data. Then, by using the information of the acquired LF, an image on the assumption that light passes through a virtual optical system and forms the image on a virtual sensor is calculated. By appropriately setting such a virtual optical system and a virtual sensor, refocus described previously is also enabled. As an image capturing device for acquiring LF, a Plenoptic Camera (for example, Japanese Patent Laid-Open No. 2009-124213) in which a microlens array is arranged behind a main lens, and a camera array in which compact cameras (image capturing modules) are arranged side by side are known. It is possible for both to obtain multi-viewpoint captured image data in which the image of a subject is captured in different directions by one-time image capturing. It is also possible to represent light field photography as calculation of an image acquired by a virtual sensor under virtual optical conditions from multi-viewpoint captured image data. In the following, processing to calculate an image acquired by a virtual sensor is referred to as “refocus processing”. As refocus processing, there is known a method in which acquired multi-viewpoint captured image data is subjected to projective transformation onto a virtual sensor, and added and averaged (for example, WO 2008/050904 pamphlet).
As a method for displaying an image having been subjected to refocus processing (hereinafter, refocus image) while changing the focus position, for example, there is a method disclosed in US 2008/0131019 A1. In this method, a user interface (UI) via which the focus position is adjusted is provided on the screen on which the refocus image is displayed and a user changes the focus position via the UI. Further, in US 2008/0131019 A1, there is disclosed a method for displaying a refocus image whose focus position has been adjusted to a subject specified by a user who desires to put the subject into focus on the screen on which the refocus image is displayed.
In the method disclosed in the above US 2008/0131019 A1, the UI for adjusting a virtual focus position used at the time of refocusing and the UI for adjusting the focus position used at the time of image capturing are different. The UI for inputting a virtual focus position at the time of refocusing and the UI for inputting the focus position at the time of image capturing exist separately from and independently of each other as described above, and therefore, it is inconvenient for a user to use them.